The invention relates to a method of manufacturing a reaction vessel for crystal growing by providing a coating of silicon dioxide on the inside of a hollow member of quartz.
Such a method is known from DE-PS No. 962868 according to which a crucible for the manufacture of high-purity semiconductor materials is manufactured by coating a crucible of high-purity quartz on its inside with silicon dioxide. The silicon dioxide is obtained by rectification of silicon tetrachloride and subsequent hydrolysis with high-purity water. In this process a gel-like mass is formed which is provided on the inside of the crucible and is sintered there at approximately 1200.degree. to 1400.degree. C.
In DE-AS No. 29 28 089 such reaction vessels are referred to as "compound crucibles" and "compound tubes", respectively.
When such reaction vessels are used for crystal growth purposes it should be ensured that the impurities present in the wall of the vessel do not diffuse into the interior of the vessel and interfere there with the growth process of the crystal. During the investigations which led to the present invention it was found that in particular a chlorine contamination has a negative effect.
The method known from DE-PS No. 962868 is not suitable to prevent the chlorine contamination because in this method silicon tetrachloride, a chlorine-containing compound, is used as a starting compound.